TOS can deliver notifications for certain event changes to Volcano Engine Function as a Service (veFaaS). You can configure event notification rules to monitor changes to resources in TOS in real time. This article presents sample code for event notification.

Learn more in What is veFaaS.

Configure Event Notification Rules

You can configure event notification rules for a specified bucket through the putBucketNotification interface of the TOS Java SDK.

warning

To configure event notification rules for a bucket, you must be the bucket Owner.

Configuring event notifications depends on the function service. You need to create and publish a function service in Volcano Engine in advance.

A maximum of 10 event notification rules can be created for a single bucket.

An event notification rule can specify only one push target, which must be a function service.

Sample Code

The following code demonstrates how to configure event notification rules for a bucket.

import com.volcengine.tos.TOSV2;​
import com.volcengine.tos.TOSV2ClientBuilder;​
import com.volcengine.tos.TosClientException;​
import com.volcengine.tos.TosServerException;​
import com.volcengine.tos.model.bucket.*;​
​
import java.util.ArrayList;​
import java.util.List;​
​
public class PutBucketNotificationExample {​
    public static void main(String[] args) {​
        String endpoint = "your endpoint";​
        String region = "your region";​
        String accessKey = System.getenv("TOS_ACCESS_KEY");​
        String secretKey = System.getenv("TOS_SECRET_KEY"); ​
​
        String bucketName = "bucket-example";​
​
        String id = "event notification id";​
        String cloudFunction = "your cloud function";​
​
        String event = "tos:ObjectCreated:Put";​
​
        TOSV2 tos = new TOSV2ClientBuilder().build(region, endpoint, accessKey, secretKey);​
​
        try{​
            List<String> events = new ArrayList<>();​
            events.add(event);​
            FilterRule rule = new FilterRule().setName("prefix").setValue("test-");​
            List<FilterRule> rules = new ArrayList<>();​
            rules.add(rule);​
            Filter filter = new Filter().setKey(new FilterKey().setRules(rules));​
            CloudFunctionConfiguration configuration = new CloudFunctionConfiguration()​
                    .setId(id).setCloudFunction(cloudFunction)​
                    .setEvents(events)​
                    .setFilter(filter);​
            List<CloudFunctionConfiguration> configurations = new ArrayList<>();​
            configurations.add(configuration);​
            PutBucketNotificationInput input = new PutBucketNotificationInput().setBucket(bucketName)​
                    .setCloudFunctionConfigurations(configurations);​
            PutBucketNotificationOutput output = tos.putBucketNotification(input);​
            System.out.println("putBucketNotification succeed");​
        } catch (TosClientException e) {​
            System.out.println("putBucketNotification failed");​
            System.out.println("Message: " + e.getMessage());​
            if (e.getCause() != null) {​
                e.getCause().printStackTrace();​
            }​
        } catch (TosServerException e) {​
            System.out.println("putBucketNotification failed");​
            System.out.println("StatusCode: " + e.getStatusCode());​
            System.out.println("Code: " + e.getCode());​
            System.out.println("Message: " + e.getMessage());​
            System.out.println("RequestID: " + e.getRequestID());​
        } catch (Throwable t) {​
            System.out.println("putBucketNotification failed");​
            System.out.println("unexpected exception, message: " + t.getMessage());​
        }​
    }​
}​

Retrieve Event Notification Rules

You can obtain the event notification rules configured for a specified bucket through the TOS Java SDK's getBucketNotification interface.

warning

By default, you must be the bucket owner to retrieve the event notification rules for a bucket.

Sample Code

The following code demonstrates how to retrieve the event notification rules for a bucket.

import com.volcengine.tos.TOSV2;​
import com.volcengine.tos.TOSV2ClientBuilder;​
import com.volcengine.tos.TosClientException;​
import com.volcengine.tos.TosServerException;​
import com.volcengine.tos.model.bucket.CloudFunctionConfiguration;​
import com.volcengine.tos.model.bucket.GetBucketNotificationInput;​
import com.volcengine.tos.model.bucket.GetBucketNotificationOutput;​
​
public class GetBucketNotificationExample {​
    public static void main(String[] args) {​
        String endpoint = "your endpoint";​
        String region = "your region";​
        String accessKey = System.getenv("TOS_ACCESS_KEY");​
        String secretKey = System.getenv("TOS_SECRET_KEY"); ​
​
        String bucketName = "bucket-example";​
​
        TOSV2 tos = new TOSV2ClientBuilder().build(region, endpoint, accessKey, secretKey);​
​
        try{​
            GetBucketNotificationInput input = new GetBucketNotificationInput().setBucket(bucketName);​
            GetBucketNotificationOutput output = tos.getBucketNotification(input);​
            System.out.println("getBucketNotification succeed");​
            if (output.getCloudFunctionConfiguration() != null) {​
                System.out.println("this bucket has " + output.getCloudFunctionConfiguration().size() + " notification rules");​
                for (int i = 0; i < output.getCloudFunctionConfiguration().size(); i++){​
                    CloudFunctionConfiguration conf = output.getCloudFunctionConfiguration().get(i);​
                    System.out.println("Cloud Function Configuration ID:" + conf.getId());​
                    if (conf.getEvents() != null && conf.getEvents().size() > 0) {​
                        for(int j = 0; j < conf.getEvents().size(); j++) {​
                            System.out.println("Cloud Function Configuration Events " + j + " is " + conf.getEvents().get(j));​
                        }​
                    }​
                    System.out.println("Cloud Function Configuration Filter " + conf.getFilter());​
                    System.out.println("Cloud Function Configuration CloudFunction " + conf.getCloudFunction());​
                }​
            }​
        } catch (TosClientException e) {​
            System.out.println("getBucketNotification failed");​
            System.out.println("Message: " + e.getMessage());​
            if (e.getCause() != null) {​
                e.getCause().printStackTrace();​
            }​
        } catch (TosServerException e) {​
            System.out.println("getBucketNotification failed");​
            System.out.println("StatusCode: " + e.getStatusCode());​
            System.out.println("Code: " + e.getCode());​
            System.out.println("Message: " + e.getMessage());​
            System.out.println("RequestID: " + e.getRequestID());​
        } catch (Throwable t) {​
            System.out.println("getBucketNotification failed");​
            System.out.println("unexpected exception, message: " + t.getMessage());​
        }​
    }​
}​